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A-ball-rolled-on-ice-with-a-velocity-of-14-ms-1-comes-to-rest-after-travelling-40-m-Find-the-coefficient-of-friction-Given-g-9-8-m-s-2-




Question Number 20349 by Tinkutara last updated on 25/Aug/17
A ball rolled on ice with a velocity of  14 ms^(−1)  comes to rest after travelling  40 m. Find the coefficient of friction.  (Given, g = 9.8 m/s^2 )
$$\mathrm{A}\:\mathrm{ball}\:\mathrm{rolled}\:\mathrm{on}\:\mathrm{ice}\:\mathrm{with}\:\mathrm{a}\:\mathrm{velocity}\:\mathrm{of} \\ $$$$\mathrm{14}\:\mathrm{ms}^{−\mathrm{1}} \:\mathrm{comes}\:\mathrm{to}\:\mathrm{rest}\:\mathrm{after}\:\mathrm{travelling} \\ $$$$\mathrm{40}\:\mathrm{m}.\:\mathrm{Find}\:\mathrm{the}\:\mathrm{coefficient}\:\mathrm{of}\:\mathrm{friction}. \\ $$$$\left(\mathrm{Given},\:{g}\:=\:\mathrm{9}.\mathrm{8}\:\mathrm{m}/\mathrm{s}^{\mathrm{2}} \right) \\ $$
Commented by Tinkutara last updated on 25/Aug/17
Just tell the answer. Is it 0.25 or 0.5?
$$\mathrm{Just}\:\mathrm{tell}\:\mathrm{the}\:\mathrm{answer}.\:\mathrm{Is}\:\mathrm{it}\:\mathrm{0}.\mathrm{25}\:\mathrm{or}\:\mathrm{0}.\mathrm{5}? \\ $$
Commented by ajfour last updated on 25/Aug/17
faulty question, not clear whether  ball rolls or just slides, what type  of ball, what radius...  did it start rolling since beginning  it should not stop, friction wont  even act then  if it just slides then  μmgx=(1/2)mv^2   ⇒ μ=(v^2 /(2gx))=((196)/(2×9.8×40)) = 0.25
$${faulty}\:{question},\:{not}\:{clear}\:{whether} \\ $$$${ball}\:{rolls}\:{or}\:{just}\:{slides},\:{what}\:{type} \\ $$$${of}\:{ball},\:{what}\:{radius}… \\ $$$${did}\:{it}\:{start}\:{rolling}\:{since}\:{beginning} \\ $$$${it}\:{should}\:{not}\:{stop},\:{friction}\:{wont} \\ $$$${even}\:{act}\:{then} \\ $$$${if}\:{it}\:{just}\:{slides}\:{then} \\ $$$$\mu{mgx}=\frac{\mathrm{1}}{\mathrm{2}}{mv}^{\mathrm{2}} \\ $$$$\Rightarrow\:\mu=\frac{{v}^{\mathrm{2}} }{\mathrm{2}{gx}}=\frac{\mathrm{196}}{\mathrm{2}×\mathrm{9}.\mathrm{8}×\mathrm{40}}\:=\:\mathrm{0}.\mathrm{25} \\ $$
Commented by Tinkutara last updated on 25/Aug/17
Thanks, 0.25 I wanted.
$$\mathrm{Thanks},\:\mathrm{0}.\mathrm{25}\:\mathrm{I}\:\mathrm{wanted}. \\ $$

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